Stable-surface alloy steel



Patented, May 20, 1930 UNITED STATES PATENT' OFFICE RALPH 1'. DE vRIEs, NEw'roNvILLE, NEW YoEK, ASSIGNOR To LUDLUM STEEL COMPANY, or WATERVLIET, NEW YORK, A CORPORATION OF NEW JERSEY STABLE-SURFACE ALLOY STEEL No Drawing.

This invention relates to alloys of steels,

and more particularly to such alloys as are ,knoivn to the trade as stable-surface alloy stee s.

5 The main objects ofmy invention are to provide an alloy steel of new composition which will be resistant to scaling action at high temperatures ranging from a low red heat to temperatures as high as 1800 F., and

which will be resistant to varying degrees to rusting-acids and corroding agents of various kinds. This steel may be readily forged and rolled, and when it has been thus forged and rolled, it will have good strength and fair ductility.

The invention is especially useful where steels are to be used for internal combustion engine poppet valves, electrical resistance heating elements, carburizing boxes, and for 2 other purposes wherein metal is desired which will resist scaling, particularly at high temperatures.

An alloy steel containing as its essential elements carbon and aluminum within the ranges of my resent invention, with iron as the balance 0 the alloy, has fairly good resistance to scaling and towards action of corrodin agents of various kinds. When such an al oy however, contains percentages of aluminum, which mm above 2 to 3%, it becomes decidedly inferior with regard to its physical strength and ductilityr When much higher percentages of aluminum than'2' to 3% are used, the alloy becomes useless for most structural and engineering purposes.

I have discovered that'copper may be added to-such an alloy in substantial amounts and that when so added it roduces a steel havin the desired qualities of strength and ductility, as well as resistance to scalmg'at high temperatures. Such steels containing percentages of aluminum as high as 6.0% may then be readily forged, rolled or worked, in any manner desired, and have when thus forged or rolled, the desired characteristics mentioned above.

An alloy steel made in accordance with my invention contains aluminum from 1.5% to 6.0% and copper from 0.5% to 6.0%. I have also discovered that when the aluminum con- Application filed January 22, 1926. Serial No. 83,139.

tent is raised to any point above 2.5% the amount of copper in the alloy must not be below 2.0%, and when the alloy contains over 3.0% of aluminum, it is necessary to add at least 5.0% of copper for many purposes.

Alloys of this composition can be melted practically carbon free, but for some purposes may contain carbon as high as 1.0%. The usual amount of manganese found in tool and structural steels may be present, or slightly greater amounts upto 1.5% may be used. Impurities and metalloids, such as sulphur, phosphorus, etc., will be kept as low as possible. Typical examples of this alloy may be noted as having the following composition, it being understood that the iron balance may include the manganese, impurities and metalloids as above stated:

Carbon Copper 533 Iron Per cent Per cent Per cent 0. 25 3. 00 5 00 Balance 0. 32 1. 5 3. 0 Balance a It is awell known factthat aluminum in the highest proportions herein mentioned makes a very coarse grain alloy of very little strength. The copper in this alloy overcomes this objection. It produces an alloy which can be forged, and which has good strength. For still'further refining the grain, titanium may be added in amounts running from as low as 0.1% up to 5.0%. Where it is desired to impart to. the alloy which is to be subjected to high temperatures, greater strength at high temperatures, I may add tungsten or g molybdenum in percentages 0.5% to 5.0%, to

obtain additional strength at high temperatures.

.Alloy steels made in accordance with my invention can be readily hardened by heating above their critical ranges and then cooling in water, oil, or air as desired. For many purposes for which this alloy steel is adapted, it will be desirable to vary the physical properties by heat treatment which may con sist of hardening as mentioned and drawing the steel by re-heating after such hardening. 100

I claim- 1. As a new roduct, a stable surface alloy steel capable being worked and comprising aluminum from 1.5% to 6.0%, copper from 0.5% to 6.0%, carbon from 0.05% to 1.0%, and the balance iron. 7

2. A stable surface alloy steel capable of being worked and comprising as essentials of the alloy, aluminum from 1.5% to 6.0%, m and copper from 0.5% to 6.0%.

3. A stable-surface alloy steel capable of being worked and comprising as essentials of the alloy, aluminum from 1.5 to 6.0%, copper from 0.5% to 6.0%, and a 'grain refiner.

4. A stable surfacealloy steel capable of being worked and comprising as essentials of the alloy, aluminum from 1.5% to 6.0%, copper from 0.5% to 6.0%, titanium from 0.1% to 5.0%.

5. As a new product, a stable surface alloy steel capable of being worked and comprising alloying elements in amounts of the orders of magnitude as follows :-aluminum 1.5%- 4%, copper 0.5%6%, carbon 0.05%1%.

6. As a new product, a stable surface alloy steel capable of being worked and comprising, as essentials of the alloy, aluminum in an amount of the order of 1.5%4% and copper of the order of 0.5%6%.

so In testimony whereof I have signed my name to this specification.

RALPH P. DE VRIES. 

